The book is introduced with the author’s scientific odyssey in the quest for the secretive vampire moths, initiated more than half a century ago in Southeast Asia and nearby regions. The main part of the book presents a synthesis of three decades of research based mainly on his nocturnal field investigations in or near forest habitats. What would appear as perverted feeding habits in insects generally thought as gentle flower visitors are exposed as sophisticated adaptations developed in a select group of less than ten of the 180 000 known species of Lepidoptera. Calyptra’s unique skin-piercing blood-sucking methods are detailed in photographs and diagrams. The moths’ victims range from elephants and rhinoceroses, to tapirs, horses, cattle, deer and pig, and occasionally humans. Other aspects treated include distribution, behaviour, ecology, phenology, and physiology. An identification key facilitates recognition of all Calyptra species (not all are blood suckers), enhanced by illustrations and descriptions of moth adults, their caterpillars and host plants. The moths’ veterinary-medical implications are discussed in the light of their being among the largest of all blood-sucking insects, combined with their unorthodox mode to bleed their quarry. The book is rounded off reviewing the most probable scenarios of the moths’ evolutionary pathway into blood suckers, and added with a comprehensive list of the subject’s literature.